1. Field of the Invention
The present invention relates to a method for controlling to cool a communication station, wherein an inside of the communication station, accommodating communication equipments including heat elements such as boards, are cooled by a cooling device such as an air conditioner.
The present invention also relates to an improvement of a system for cooling a casing of a communication station, wherein an inside of the casing, accommodating communication equipments including heat components, is cooled by a boiling type cooler in a natural circulation refrigerating circuit and an evaporator in a forced circulation refrigerating circuit, circulated by a compressor.
2. Discussion of Background
In recent years, communication stations including a large number of electronical boards for communication are located in various places for relaying communications along with expanding popularization of portable communication apparatuses. Dimensions of such communication relay stations are, for example, a width of about 6 m, a depth of about 1.7 m, and a height of about 1.7 m. Although the communication relay stations are relatively small, a gloss colorific value of electronical boards, equipped in the communication stations, are several kW through several dozens of kW. Therefore, air conditioners are used to cool these electronic boards by cooling board casings of the communication stations. FIG. 33 illustrates a structure of a conventional method for controlling to cool a communication station. In FIG. 33, numerical reference 1 designates a rack accommodating a communication equipments including a large number of electronic boards and so on; numerical reference 3 designates a fan; numerical reference 4 designates an indoor unit including an indoor heat exchanger 4a and an indoor fan 4b; numerical reference 5 designates an outdoor unit including a compressor 5a and an outdoor heat exchanger 5b; numerical reference 6 designates a suction air into the indoor heat exchanger 4a; numerical reference 7 designates a blown-out air from the indoor heat exchanger 4a; numerical reference 8 designates a suction air for cooling the communication equipment 2; numerical reference 9 designates a suction air temperature detector for detecting a temperature of the suction air 6; numerical reference 10 designates a casing for accommodating the lack 1 and the indoor unit 4; and numerical reference 11 designates a cooling controller for controlling a cooling capability of the compressor 5a. 
In the next, an operation of the conventional method for controlling to cool the communication station will be described. The number of operating communication equipments 2 is changed in response to a frequency of communication, and a colorific value is increased or decreased in response to the number of operating communication equipments 2. The suction air 8 to the communication equipments 2 is sent by the fan 3 to cool the communication equipments 2, is heated after cooling, and is taken in the indoor unit 4 as the suction air 6 into the indoor heat exchanger 4a. The suction air 6, taken into the indoor unit 4, is cooled by the indoor heat exchanger 4a, is blown out into the casing 10 as the blown-out air 7 from the indoor heat exchanger 4a, and is served as the suction air 8 into the communication equipments 2. On the other hand, the cooling controller 11 controls a cooling capability of the compressor 5a based on an output temperature of the suction air temperature detector 9 so that the suction air 8 into the communication equipments 2 becomes a predetermined temperature, for example, 35xc2x0 C. or less.
Further, a large number of communication stations for handy personal phones and so on are located in cities, rooftops of condominiums and office buildings, mountain tops in the suburbs, and wilds. Communication equipments are generally accommodated in a sealed casing in the communication stations. However, some of casings have a space too narrow to receive a person. Therefore, the casings are adequately cooled because heat components are included in the communication equipments.
As a system for cooling such a casing is disclosed in Japanese Unexamined Patent Publication JP-A-11-135972. FIG. 34 illustrates this system. The casing cooling system 151 for a communication station 152 is composed of a boiling type cooler 121 in a natural circulation refrigerating circuit 120 and an evaporator 113 in a forced circulation refrigerating circuit 109 so as to cool an inside of the casing 103 as the sealed space. The forced circulation refrigerating circuit 109 is constructed to forcibly circulate a refrigerant by a compressor 110, which mechanism is generally used in an air conditioner and so on. Communication equipments 104 including heat components 105 are accommodated in the casing 103. In generally used communication equipments 104, a fan (not shown) is located inside an equipment case 106 having built-in heat components 105 to take an air from an intake port 107, located on a side surface or a bottom surface of the equipment case, and to blow a heat out of an exhaust port 108, positioned on a back of the equipment case.
In a case of an evaporator, an intake port 155 for taking an air inside the casing 103 and an exhaust port for blowing a cooled air into the casing 103 are formed. In the case 153 of the evaporator, the evaporator 113 and a fan 154 are built. On the other hand, on a back surface of the equipment case 106, a heated air guide path 157, connected to the exhaust port 108, is formed. The heated air guide path 157 is connected to an air path 167 having a heated air intake port and a heated air exhaust port. A condenser 122 and a fan 163 are built in the air path 167.
A condenser 111 in the force circulation refrigerating circuit 109 is located in a case of a condenser as an outdoor unit of an air conditioner. The case 117 of the condenser is formed like a box having an outer air intake port 118 and an exhaust port 119. The condenser 111, the compressor 110, a choke valve 112 for refrigerant, and a fan 116 are housed in the case 117 of the condenser. The forced circulation refrigerating circuit 109 is constructed by sequentially connecting the compressor 110, the condenser 111, the refrigerant choke valve 112 in the condenser case 117 with the evaporator 113 in the casing 103 via tubes 114, 115 for the refrigerant so as to be shaped like a ring. Further, the condenser 122 in the natural circulation refrigerating circuit 120 is disposed in the condenser case 159 as an outdoor unit. The condenser case 159 is shaped like a box having an outer air intake port 160, an exhaust port 161, the condenser 122, the fan 162. The natural circulation refrigerating circuit 120 is constructed by connecting the condenser 122 in the condenser case 159 with the boiling type cooler 121 in the airflow path 167 via a refrigerant evaporation tube 123 and a liquid refrigerant return tube 124 so as to be shaped like a ring.
In the conventional cooling system, a cooling capability is determined in conformity with a maximum load of the heat components 105. Because the casing 103 generally has a structure having an extremely small heat transfer through solid conductors, there are very small variations of a cooling load inside the casing 103 in response to variations of an outer air temperature.
In the next, an operation of the conventional system will be described. An air in the casing 103 is taken in the equipment case 106 through the air intake port 107 when a fan in the communication equipments 104 (not shown) is driven. A cooling air, taken in, cools the heat components 105 and is changed to be a heated air. Thereafter, the heated air is blown out of the exhaust port 108 in the back surface of the case into the heated air guide path 157. Thus blown-out heated air is sucked in the airflow path 167 through the heated air intake port 158 by the fan 163. The heated air passes through the boiling type cooler 121 in the airflow path 167 and primarily cooled by changing heat with a refrigerant in the natural circulation refrigerating circuit 120. The air subjected to the primary cooling is sucked by the fan 163 and blown into the casing 103 through the exhaust port 164. At least a part of the air subjected to the primary cooling is sucked into the evaporator case 153 through the intake port 155 by the fan 154 and passes through the evaporator 113, whereby the air is cooled by changing heat with a refrigerant in the forced circulation refrigerating circuit 109. Thus cooled air is blown out of the cooling air exhaust port 156 into the casing.
In the natural circulation refrigerating circuit 120, a refrigerant in the boiling type cooler 121 is boiled by changing heat with the heated air so as to be a gas refrigerant. The gas refrigerant passes through the refrigerant evaporation tube 123 and reaches the condenser 122. The gas refrigerant in the condenser 122 is changed to a liquid refrigerant by changing heat with an outer air passing from the outer air intake port 160 to the exhaust port 161 in a condenser case 159, wherein the gas refrigerant is cooled. The liquid refrigerant returns to the boiling type cooler 121 through the liquid refrigerant return tube 124 by a gravity flow caused by a difference of weight densities between the liquid refrigerant and the gas refrigerant. On the other hand, in the forced circulation refrigerating circuit 109, a high-temperature high-pressure gas refrigerant, forcibly discharged out of the compressor 110, flows into the condenser 111 and is changed to be a liquid refrigerant by exchanging heat with an outer air flowing from the outer air intake port 118 to the exhaust port 119 in the condenser case 117 by the fan 116, wherein the high-temperature high-pressure gas refrigerant is cooled. The liquid refrigerant is depressurized by the refrigerant choke valve 12 to be a gas-liquid two-phase state. Thereafter, the liquid refrigerant reaches the evaporator 113 through the refrigerant tube 114. The refrigerant exchanges heat with an air flowing through the evaporator case 153 in the evaporator 113 so as to be a low-pressure gas refrigerant. The refrigerant returns to an intake side of the compressor 110 through the refrigerant tube 115.
In the conventional cooling control method for communication stations, because an ordinary wall-hang or dangling-type package air conditioner is used as disclosed in Japanese Unexamined Patent Publication JP-A4-98038, a suction temperature 6 of the indoor heat exchanger 4a is detected by the suction temperature detecting means 9. However, in case that an air distribution in the casing is not preferable, there occur phenomenons that exhausted heat from the communication equipments resides and an air blown out of the indoor unit causes a short cycle. Accordingly, a calorific value of the communication equipments, i.e. a real cooling load, does not in conformity with the suction air temperature 6. Accordingly, the air conditioner does not deal with the real cooling load, whereby a temperature in the casing is increased or decreased; and environmental conditions of working temperature of the communication equipments are resultantly unsatisfied, and vapor is condensed in the air conditioner.
Meanwhile, in the conventional cooling system, because the boiling type cooler 121 and the evaporator 113 are located in the different airflow paths, it is necessary to locate fans 163 and 154 respectively for the airflow paths.
Further, because a density of components installed in the casing 103 is high in order to pursue compactness, it is impossible to provide a space for additional fans. Therefore, there is a problem that a large-sized fan can. not be used, for example, a large airflow rate can not be supplied when the space of the casing 103 is unchanged.
Incidentally, because the air, primarily cooled in the boiling type cooler 121, diffuses in the casing 103 after passing through the exhaust port 164, a part of the airflows toward the evaporator case 153, like an arrow C, and the other parts are sucked in the air intake port 107 of the communication equipment 104 by bypassing like an arrow B. When an airflow rate of the fan 154 is excessively large, the cooled air, blown out of the cooling air exhaust port 156, may return to the intake port 155 by a short cycle, whereby cooling efficiency is deteriorated.
Further, in order to take the heated air in the boiling type cooler 121, it is necessary to locate the heated air guide path 157 and the heated air intake port 158, whereby a structure of airflow path becomes complicated. If the heated air guide path 157 is not located, a high-temperature heated air, blown out of the exhaust port 108 of the communication equipments 104, is directly sucked into the suction port 155 of the evaporator 113 by bypassing the boiling type cooler 121, whereby there is a danger that the forced circulation refrigerating circuit 109 is broken.
It is an object of the present invention to solve the above-mentioned problems inherent in the conventional technique and to provide a cooling control method for communication stations, by which communication equipments can be cooled in response to a variation of a calorific value, caused by the number of operations of the communication equipments. Further, it is possible to control with a good follow-up capability; a cooler can be highly efficiently operated by saving an energy; moisture condensation can be prevented; frequent turning-ons and turning-offs of an air conditioner can be prevented; it is possible to deal with environmental changes; and a COP of the cooler can also be increased; and other improvements can be obtained.
Further, another object of the present invention is to provide a cooling control method for communication stations, by which moisture condensation, caused by excessive drop of a temperature of a blowing-out air from an indoor unit can be prevented.
Another object of the present invention is to provide a cooling system for a casing of communication stations, by which a capacity of the total volume of the cooling system is optimized, an energy is saved, and reliability of the system can be improved by appropriately combining a boiling-type cooler in a natural circulation refrigerating circuit, an evaporator in a forced circulation refrigerating circuit, and fans.
According to a first aspect of the present invention, there is provided a cooling system for a communication station for cooling a casing of the communication station, accommodating communication equipments including heat components, by a boiling-type cooler in a natural circulation refrigerating circuit and an evaporator in a forced circulation refrigerating circuit, activated by a compressor comprising:
a common airflow path having a heated air intake port for taking a heated air into the casing and a cooled air exhaust port for blowing a cooled air into the casing; and
a common fan for sending an air to the boiling-type cooler and the evaporator,
wherein the boiling-type cooler, the evaporator, and the common fan are built in the common airflow path.
According to a second aspect of the present invention, there is provided the cooling system for the communication station,
wherein the common airflow path is constructed by an air path on a cooler side, inside which the boiling-type cooler is installed, an air path on an evaporator side, in which the evaporator is installed, and a connection air path for connecting the air path on the cooler side and the air path on the evaporator side.
According to a third aspect of the present invention, there is provided the cooling system for the communication station further comprising:
a temperature detecting means for detecting at least an outer air temperature; and
a compressor control means for stopping an operation of the compressor in the forced circulation refrigerating circuit based on a detected temperature received from the temperature detecting means.
According to a fourth aspect of the present invention, there is provided the cooling system for the communication station further comprising:
a malfunction detecting means for detecting malfunctions of the forced circulation refrigerating circuit; and
a driving means for keeping the common fan in a running state when the malfunctions in the forced circulation refrigerating circuit are detected by the malfunction detecting means.
According to a fifth aspect of the present invention, there is provided a cooling controlling method for a communication station having an air conditioner, and a casing for accommodating communication equipments comprising:
an electric power detecting means for detecting a power consumption of the communication equipments, accommodated in the casing; a suction temperature detecting means for detecting a temperature of an air, sent to the communication equipments; and a cooling control means for controlling a capability of the air conditioner,
wherein the cooling control means controls the capability of the air conditioner based on an output from the electric power detecting means and an output from the suction temperature detecting means.
According to a sixth aspect of the present invention, there is provided the cooling control method for the communication station,
wherein the capability the compressor of the air conditioner is minimized in case that the output from the electric power detecting means is smaller than a predetermined electrical power by the cooling control means.
According to a seventh aspect of the present invention, there is provided a cooling control method for a communication station having a casing accommodating an air conditioner and communication equipments comprising:
a suction temperature detecting means for detecting a suction temperature of an indoor heat exchanger;
a suction temperature detecting means for detecting a temperature of an air, sent to the communication equipments; and
a cooling control means for controlling a capability of the air conditioner,
wherein the capability of the air conditioner is controlled based on an output from the suction temperature detecting means for the indoor heat exchanger and the suction temperature detecting means for the communication equipments by the cooling control means.
According to an eighth aspect of the present invention, there is provided the cooling control method for the communication station,
wherein the capability of the compressor of the air conditioner is minimized in case that an output from the suction temperature detecting means for the indoor heat exchanger is lower than a predetermined temperature.
According to a ninth aspect of the present invention, there is provided a cooling control method for a communication station having a casing accommodating an air conditioner and communication equipments comprising:
an electric power detecting means for detecting an electric power consumption of the communication equipments, accommodated in the casing;
a suction temperature detecting means for detecting a suction temperature of an indoor heat exchanger;
a suction temperature detecting means for detecting a temperature of an air sent to the communication equipments; and
a cooling control means for controlling a capability of the air conditioner,
wherein the capability of the air conditioner is controlled by the cooling control means based on an output from the electric power detecting means, an output from the suction temperature detecting means for the indoor heat exchanger, and an output from the suction temperature detecting means for the communication equipments.
According to a tenth aspect of the present invention, there is provided the cooling control method for the communication station,
wherein a capability of the compressor of the air conditioner is minimized in case that the output from the electric power detecting means is smaller than a predetermined electrical power, or an output from the suction temperature detecting means for the indoor heat exchanger is smaller than a predetermined temperature.
According to an eleventh aspect of the present invention, there is provided the cooling control method for the communication station,
wherein the electric power consumption is detected by the electrical power detecting means based on a total electric current through the communication equipments accommodated in the casing.
According to a twelfth aspect of the present invention, there is provided a cooling control method for a communication station having a casing, accommodating an air conditioner and communication equipments comprising;
a suction temperature detecting means for detecting a temperature of an air sent to the communication equipments;
a suction temperature detecting means for detecting a temperature of a suction air into an indoor heat exchanger; and
a cooling control means for controlling a capability of the air conditioner and for changing a control target value of a temperature of an air sent to the communication equipments,
wherein the cooling control means controls the capability of the air conditioner based on an output from the suction temperature detecting means for the communication equipments and the control target value of the temperature of the air, sent to the communication equipments, and changes the control target value of the temperature of the air, sent to the communication equipments, based on an output from the suction temperature detecting means for the indoor heat exchanger.
According to a thirteenth aspect of the present invention, there is provided the cooling control method for the communication station,
wherein the cooling control means changes the control target value of the temperature of the air, sent to the communication equipments, based on a target value of the suction air temperature into the indoor heat exchanger and the output from the suction temperature detecting means for the indoor heat exchanger, and
the cooling control means decreases the target value of the suction air temperature into the indoor heat exchanger by a predetermined temperature in case that at least one of phenomenons that the suction temperature into the communication equipments, detected by the suction temperature detecting means for the communication equipments, exceeds a predetermined limit value and that the air conditioner is turned on for predetermined numbers or more.
According to a fourteenth aspect of the present invention, there is provided the cooling control method for the communication station,
wherein an upper limit value and a lower limit value of the suction air temperature are controlled by the cooling control means based on the target value of the suction air temperature for the indoor heat exchanger and the control target value of the temperature of the air, sent to the communication equipments.
According to a fifteenth aspect of the present invention, there is provided the cooling control method for the communication station,
wherein an initial value of the control target value is set by the cooling control means by every predetermined period.
According to a sixteenth aspect of the present invention, there is provided the cooling control method for the communication station further comprising:
an auxiliary cooling device besides the air conditioner, served as a main cooling device,
wherein an operation of the auxiliary cooling device is controlled independently of the main cooling device.
According to a seventeenth aspect of the present invention, there is provided the cooling control method for the communication station further comprising:
an ebullient cooling device as an auxiliary cooling device besides the air conditioner, served as a main cooling device, and
an evaporator for the ebullient cooling device located on an upstream side in an airflow path, in which the indoor heat exchanger of the main cooling device is located,
wherein the main cooling device controls to cool an air, cooled by the ebullient cooling device.
According to an eighteenth aspect of the present invention, there is provided the cooling control method for the communication station,
wherein a blower of an outdoor unit of the ebullient cooling device is stopped in case that the detected temperature by the suction temperature detecting means for the indoor heat exchanger is smaller than a predetermined value.
According to a nineteenth aspect of the present invention, there is provided a cooling control method for a communication station comprising:
a suction temperature detecting means for detecting a suction air temperature into an indoor heat exchanger; and
a cooling control means for controlling an air conditioner based on the suction air temperature, outputted from the suction temperature detecting means and a suction air temperature, outputted from a suction temperature detecting means for communication equipments, and for controlling a cooling capability of the air conditioner in case that an electric power consumption of the communication equipments outputted from an electric power detecting means is a predetermined value or less.
According to a twentieth aspect of the present invention, there is provided a cooling control method for communication station comprising:
an electric power detecting means for detecting an electric power consumption;
a suction temperature detecting means for communication equipments; and
a cooling control means for controlling an air conditioner based on outputs from the electrical power detecting means and the suction temperature detecting means, and for control a cooling capability of the air conditioner to be minimum in case that a suction temperature into an indoor unit, outputted by a suction temperature detecting means for the indoor heat exchanger, is a predetermined value or less.